Rear crash management system (CMS)

ABSTRACT

A rear impact system for an electric vehicle, the rear impact system includes a rear crash element extending laterally along a rear of the electric vehicle. The rear crash element defines an interior having a number of ribs extending between a front surface and a rear surface of the rear crash element. The system includes a left crash beam coupled between a rear portion of a rear wheel arch of the electric vehicle and the rear crash element of the electric vehicle and a right crash beam coupled between the rear portion of the rear wheel arch and the rear crash element of the electric vehicle.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. ProvisionalApplication No. 62/384,298, filed Sep. 7, 2016, the entire contents ofwhich are hereby incorporated by reference for all purposes.

BACKGROUND OF THE INVENTION

There are many problems unique to electric vehicles, oftentimes due tothe presence of large and/or numerous batteries used to power theelectric motor and other components of the vehicle. These batteries areoften bulky, and add significant weight to the vehicles. Theseconsiderations present challenges in designing a particularly efficientand practical electrical vehicle. Additionally, these batteries may beparticularly susceptible to damage during a collision. Damage to abattery may be especially dangerous by presenting a fire and/orcorrosive hazard. As such, protecting the batteries from damage remainsa difficult challenge unique to the field of electric vehicles.

Vehicle manufacturers have added a number of new structural features tovehicles to improve safety and/or performance. Many of these structuralfeatures are applicable to electric, hybrid, and non-electric vehiclesequally, while others place a greater emphasis on the vehicle motortype, such as a vehicle base plate with increased thickness forprotecting an electric car battery over a specific region of thevehicle. Structural improvements that increase either safety orperformance without a significant compromise of the other remainimportant objectives of vehicle manufacturers.

Electric vehicles are becoming an increasingly viable alternative totraditional vehicles with internal combustion engines. Electric vehiclesmay have advantages in their compactness, simplicity of design, and inbeing potentially more environmentally friendly depending on the meansby which the electricity used in the vehicle was originally generated.The prospect of using renewable energy sources to power automobiles inplace of gasoline has obvious advantages as oil reserves across theglobe become increasingly depleted.

BRIEF SUMMARY OF THE INVENTION

In one aspect, a rear impact system for an electric vehicle is provided.The rear impact system may include a rear crash element extendinglaterally along a rear of the electric vehicle. The rear crash elementmay define an interior comprising a plurality of ribs extending betweena front surface and a rear surface of the rear crash element. The rearimpact system may also include a left crash beam coupled between a rearportion of a rear wheel arch of the electric vehicle and the rear crashelement of the electric vehicle and a right crash beam coupled betweenthe rear portion of the rear wheel arch and the rear crash element ofthe electric vehicle.

In another aspect, a rear impact system for an electric vehicle mayinclude a rear crash element extending laterally along a rear of theelectric vehicle. The rear crash element may include a right surface, aleft surface, a front surface, and a rear surface that define aninterior having a plurality of ribs extending between a front surfaceand a rear surface of the rear crash element. The top surface and thebottom surface may have different widths. The rear impact system mayalso include a left crash beam coupled between a rear portion of a rearwheel arch of the electric vehicle and the rear crash element of theelectric vehicle and a right crash beam coupled between the rear portionof the rear wheel arch and the rear crash element of the electricvehicle.

In another aspect, a method of absorbing a rear impact with an electricvehicle is provided. The method may include receiving a collision at arear end of the electric vehicle and absorbing force using a pluralityof ribs of a rear crash element of the electric vehicle. The rear crashelement may define an interior comprising the plurality of ribs. Each ofthe plurality of ribs may extend between a front surface and a rearsurface of the rear crash element. The method may also includetransferring force from a rear edge of the rear crash element to atleast one crash beam that is coupled with a front edge of the rear crashelement and transferring a force from the collision from a rear edge ofthe at least one crash beam to a medial portion of the at least onecrash beam. The at least one crash beam may be coupled with a rearportion of a rear wheel arch of the electric vehicle and extending tothe rear end of the electric vehicle. The method may further includetransferring any remaining portion of the force to the rear end of therear wheel arch.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of variousembodiments may be realized by reference to the following figures. Inthe appended figures, similar components or features may have the samereference label. Further, various components of the same type may bedistinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If only the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

FIG. 1 depicts an electric vehicle according to embodiments.

FIG. 2 depicts a rear shock tower of an electric vehicle according toembodiments.

FIG. 3 depicts a rear view of a rear impact system according toembodiments.

FIG. 4 depicts a bottom view of a rear impact system according toembodiments.

FIG. 5 depicts a side view of a rear impact system according toembodiments.

FIG. 6 depicts a side view of a coupling between a rear wheel arch and arear crash beam according to embodiments.

FIG. 7 depicts a rear isometric view of a bumper mounting according toembodiments.

FIG. 8 depicts a rear isometric view of a rear impact system accordingto embodiments.

FIG. 9 depicts a bottom view of a rear impact system according toembodiments.

FIG. 10 is a flowchart depicting a method for absorbing a rear impactwith an electric vehicle according to embodiments.

DETAILED DESCRIPTION OF THE INVENTION

The subject matter of embodiments of the present invention is describedhere with specificity to meet statutory requirements, but thisdescription is not necessarily intended to limit the scope of theclaims. The claimed subject matter may be embodied in other ways, mayinclude different elements or steps, and may be used in conjunction withother existing or future technologies. This description should not beinterpreted as implying any particular order or arrangement among orbetween various steps or elements except when the order of individualsteps or arrangement of elements is explicitly described.

The systems and methods described herein relate generally toimprovements for electric vehicles. Due to the size and weightconsiderations of the batteries required to power such vehicles, as wellas the need to make electric vehicles as safe as possible, eachcomponent within the electric vehicles must be designed with particularcharacteristics in mind. Specifically, considerations related to theweight and structural integrity of each component must be weighed toensure that the electric vehicles are both efficient and safe tooperate. For example, the body of the vehicle must be stiff, efficient,and lightweight. A lightweight body helps counteract the additionalweight of the batteries, which may be in the form of several largebatteries, or numerous (sometimes thousands) of smaller batteries wiredtogether. The stiff body helps make the vehicle more stable duringcornering and also helps limit damage to the body and batteries during acollision. Protection of the batteries during a collision is particularimportant, as the large number of batteries pose a significant firehazard and may also expose passengers and others to highly corrosivematerial. Due to this high safety risk, it is imperative that the bodystructure be designed to withstand high force collisions from anydirection.

Turning now to FIG. 1, one embodiment of an electric vehicle 100 isshown. While shown here as an electric automobile, electric vehicle 100may be any motorized vehicle that is powered by electricity. Forexample, electric vehicle 100 may include vehicles such as cars, buses,trains, trucks, trams, watercraft, aircraft, and/or any other type oftransportation mechanism.

Here, much of the main body 102 of the electric vehicle 100, especiallythose components designed to form the skeleton of the vehicle and thosecomponents used for collision protection, are made of aluminum or alloyscontaining aluminum, although it will be appreciated that othermaterials may be considered. Aluminum alloys provide strong, yetlightweight components that help shed weight to compensate for the highweight of the batteries necessary to power the electric vehicle. Forelectric vehicles, an increased emphasis is placed on protection of thebatteries as damage to battery cells can cause explosion and fireswithin the vehicle. Such problems are compounded due to the large amountof space batteries must occupy within electric vehicles in order tomaintain practical driving ranges. Therefore, vehicle alterations thatprovide increased protection along edges and corners of the vehiclebattery are advantageous. Such alterations may include considerationsrelated to, but not limited to providing: (1) increased rigidity of thevehicle, (2) increased absorption of energy from a collision, and (3)increased efficiency of transfer of energy/force stemming from an impactto the vehicle's body to lessen the potential impact applied to thevehicle battery and to passengers in the vehicle.

Battery elements 104 (shown in FIG. 2) are positioned underneath a floorstructure 106 of the electric vehicle 100. Such positioning providesseveral benefits. First, the battery elements are isolated from thepassenger compartment, largely by an aluminum (or other metallicmaterial) floor structure 106, which helps increase passenger safety.The placement of the battery elements 104 underneath the vehicle 100also allows the battery elements 104 to be connected to electricalsystems of the vehicle 100 from underneath the floor structure 106. Thisenables the battery elements 104 to be changed out from the exterior ofthe vehicle 100. For example, the vehicle 100 may be raised up and thebattery elements 104 may be decoupled from the underside of the vehicle100. As just one example, a number of bolts or other fasteners may beremoved and the battery elements 104 may be lowered from the vehicle100. The battery elements 104 may be disconnected and new batteryelements 104 may be connected and fastened to the underside of thevehicle 100. This allows old batteries to be replaced easily, and alsoenables a quick swap of depleted battery elements 104 for chargedbattery elements 104, serving as a method of rapidly charging thevehicle 100 for longer trips. The placement of the battery elements 104also places much of the weight of the vehicle 100 near the ground, thuslowering the center of gravity of the vehicle 100, which allows thevehicle 100 to corner better and reduces the odds of a rollover.

Unlike automobiles that utilize internal combustion engines and includedrivetrains that extend along a length of the vehicle, electric vehicle100 is driven by one or more electric motors positioned near the wheelaxles. As a result, there is no need for a longitudinal drive train. Tohelp isolate a passenger compartment 108 from the battery elements 104while providing access for connections of the battery elements 104 to beconnected to electric systems within the passenger compartment 108 andto the one or more electric motors, the passenger compartment may beprovided with a rigid tunnel 110 protruding upward from a floorstructure 106 of the passenger compartment 108. However, unlike inconventional gas-powered vehicles where a tunnel may be provided toprovide clearance for a drivetrain, rigid tunnel 110 is included toprovide clearance for a portion of the battery elements 104 used tosupply power to the electric vehicle 100. The rigid tunnel 110 may notonly provide a housing for a portion of the battery assembly, but mayserve a number of other functions. As just one example, the rigid tunnel110 may help absorb and transfer force away from passengers in the eventof a collision. In such embodiments, the rigid tunnel 110 may be formedof carbon fiber or another composite material that is extremely strongand lightweight. In other embodiments, the rigid tunnel 110 may serve aspart of an air ventilation system, with hot or cold air being vented tothe passenger compartment 108 through a portion of the rigid tunnel 110.

FIG. 2 depicts a rear shock tower of the electric vehicle 100. The rearshock tower may include a front tower support 348 positioned over afront portion of a rear wheel arch 350 of the electric vehicle 100. Thefront tower support 348 is angled toward a rear of the electric vehicle100 from a lower portion to an upper portion of the front tower support348. In some embodiments, the front tower support 348 may define a rearwall of the passenger compartment 108. For example, the front towersupport may be a support beam that is coupled with a rear seat back andthat serves as a support to maintain a position of the rear seatassembly. The rear shock tower may also include a rear tower support 352positioned over a rear portion of the rear wheel arch 350. The reartower support 352 may be angled toward a front of the electric vehicle100 from a lower portion to an upper portion of the rear tower support352 such that tops of the front tower support 348 and the rear towersupport 352 are angled toward one another. Top ends of the front towersupport 348 and the rear tower support 352 may be coupled together usinga tower bridge 354. Tower bridge 354 spans a distance between the upperend of the front tower support 348 and the upper end of the rear towersupport 352. In some embodiments, the lower ends of both the front towersupport 348 and the rear tower support 352 are coupled with the rearwheel arch 350. For example, the lower portion of the front towersupport 348 and the lower portion of the rear tower support 352 arecoupled with a top surface of the rear wheel arch 350 using a pluralityof fasteners extending through exclusions formed in the lower portion ofthe front tower support 348 and the lower portion of the rear towersupport 352.

Vehicle 100 may have a rear shock tower positioned over each rear wellarch 350. These shock towers may be coupled with one another, such as bya cross beam 356 that extends between the tower bridges 354 of the twoshock towers. The primary purpose of each shock tower is to provide asecurement site for a mounting of the rear suspension and axle. Forexample, each tower bridge 354 may be configured to receive and secure amounting of the suspension, such as a shock absorber. The rear shocktowers also provide force transfer mechanisms to help the vehicle handlebumps while driving. For example, the shock towers may disperse forcesthrough one another via the connection through the connecting crossbeam. The rear shock towers may also disperse some of the force to wheelarches 350 and the rest of the chassis 292 via front tower support 348and rear tower support 352. The connection between the suspension andthe rear shock towers allows for movement of the wheel of vehicle 100upward toward rear wheel arch 350 during the absorption of bumps anddips in the road.

The rear shock tower may be generally trapezoidal in shape, with a topof the trapezoidal shape defined by the tower bridge 354, sides of thetrapezoidal shape defined by the front tower support 348 and the reartower support 352, and a base of the trapezoidal shape defined by therear wheel arch 350. In some embodiments, additional angular supportbeams may be included to form a truss structure within the trapezoidalshape to provide additional strength to the rear shock tower.

The rear shock tower may be configured to absorb and transfer force in amanner to protect the battery elements 104 and/or the passengercompartment 108 in the event of bumps and/or dips encountered by thevehicle 100. To aid in the absorption of force, the components of therear shock tower may be formed of aluminum or aluminum alloys. The useof aluminum, rather than a more rigid material such as steel, not onlyreduces the weight of the vehicle 100, but also allows more of theenergy from bumps and/or dips to be absorbed. To further stiffen therear crash towers and to aid in handling larger forces, each of thefront tower support 348 and the rear tower support 352 defines aninterior having a number of ribs extending along a length of therespective support. The ribs may extend through the entire interior tocouple multiple walls of the support together, thus providing additionalmaterial and material thickness to absorb and transfer greater forces.For example, the front tower support 348 and the rear tower support 352may each include one or more ribs extending from the front wall to arear wall. To facilitate the formation of the ribs, the front towersupport 348 and rear tower support 352 may be extruded from aluminumsuch that the ribs are formed along with the outer walls of therespective tower support. In some embodiments, connection points betweenthe ribs and the outer walls of the tower support may taper outward suchthat a thickness near the connection point is greater than a thicknessof the rest of the ribs. Similarly, junctions of the ribs one anothermay also have greater thicknesses than the rest of the ribs. Due to itsmore complex and non-uniform structure, the tower bridge 354 may beformed of pressed or cast aluminum. The rear wheel arches 350 may alsobe formed of pressed or cast aluminum or steel to allow for theproduction of an intricate rib structure within the rear wheel arches350 to add additional strength and rigidity.

In some embodiments, the rear shock tower may include a metallic sheet(not shown) positioned between the front tower support 348, the reartower support 352, and the tower bridge 354 so as to close an openingformed between the components. The metallic sheet may include one ormore embossed portions, ribs, and/or other profiles extending along alength and/or formed within a face of the metallic sheet. Suchformations increase the stiffness of the metallic sheet.

Each rear wheel arch 350 may be coupled with a rear crash system of thevehicle 100. For example, each rear wheel arch 350 may be coupled withthe rear crash beam 358 of the electric vehicle 100. For example, therear wheel arch 350 may define a receptacle and/or flange that isconfigured to receive a front end of the rear crash beam 358. The rearcrash beam 358 may be bolted, welded, and/or otherwise secured withinthe rear wheel arch 350, such as by fastening an outer surface of therear crash beam 358 to an interior surface of the rear wheel arch 350.The rear crash beams 358 may extend rearward toward a bumper 360 of theelectric vehicle 100. The rear crash beams 358 may be coupled with thebumper 360 via one or more intervening components. For example, eachrear crash beam 358 may be coupled with a bumper mount 362. This may bedone my inserting a rear end of the rear crash beam 358 into areceptacle, flange, and/or bracket of the bumper mount 362. In otherembodiments, the rear crash beam 358 may be positioned such that a rearend of the rear crash beam 358 abuts a front edge of the bumper mount362, with a securement mechanism being used to couple the component endstogether. In some embodiments, the bumper mount 362 may be coupled witha rear crash element 364, which is in turn coupled with the bumper 360.In some embodiments, the rear crash beam 358 may define a number ofdimples 382. Dimples 382 help initiate an accordion-like crumpling ofthe rear crash beam 358 in the event of a rear collision. For example,upon impact, a rear edge of the rear crash beam 358 may be forced towardthe dimples 382. The dimples 382 allow the rear edge to be more easilypushed directly toward the main beam 358 such that the beam 358 crumpleslargely along its longitudinal axis (rather than at an angle relative tothe axis), thus absorbing a maximum amount of force.

FIG. 3 depicts a rear impact system of the electric vehicle 100. Thesystem may include at least one longitudinal crash beam 358. Forexample, a left longitudinal beam 358 may be coupled with a rear portionof a chassis 292 or rear wheel arch 350 of the electric vehicle 100 andmay extend to a rear bumper 360 of the electric vehicle 100, possiblywith one or more intervening components such as bumper mounting 362and/or crash element 364. A right longitudinal beam 358 may be coupledwith the rear portion of the wheel arch 350 and may extend to the rearbumper 360. The longitudinal crash beams 358 may be bolted, welded,and/or otherwise fastened to the rear wheel arch 350 and/or bumpermounting 362. The longitudinal beams 358 may also be coupled with one ormore components of the vehicle 100. For example, a side of thelongitudinal beams 112 may be coupled with one or more body members ofthe vehicle 100 and/or other structural elements such as those defininga motor compartment and/or trunk. Oftentimes, the right and leftlongitudinal crash beams 358 are spaced apart along a rear of thevehicle 100. For example, the right and left longitudinal crash beams358 may be separated by a trunk and/or a motor housing. The longitudinalcrash beams 358 may be configured to absorb and transfer force in amanner to protect the battery elements 104 and the passenger compartment108. For example, the right and left longitudinal crash beams 358 mayeach be formed of aluminum or aluminum alloys.

The use of aluminum, rather than a more rigid material such as steel,not only reduces the weight of the vehicle 100, but also allows more ofthe energy from a collision to be absorbed, such as by designing thealuminum longitudinal crash beams 358 to crumple in an accordion-likemanner. Such crumpling may be achieved using several design features.For example, dimples 382 may provide some clearance to allow an impactedportion of the beam 358 to compact against a more inward portion of thebeam 358 opposite the dimple 382. This allows the beam 358 to crumplelargely along its longitudinal axis to absorb a greatest amount of forcepossible, and possibly significantly more force than crumping at anangle relative to the longitudinal axis. Dimples 382 are offset from anend of the beam 358 such that they are disposed slightly inward of therear end of the beam 358. Dimples 382 are typically formed at corners ofthe profile of each beam 358 such that each of the dimples is formed intwo side walls of the longitudinal crash beam 358. While it is possibleto create one indentation around all or a substantial portion of theouter periphery of the beams 358, this may result in the beam 358 beingable to handle smaller forces before it crumples, yields, or otherwisedeforms.

The desired crumpling may also be aided by outer walls of the right andleft longitudinal crash beams 358 being chamfered and/or the walls beinggenerally octagonal in shape. At just one example, an outer periphery ofeach of the right and left longitudinal crash beams 358 may include atop wall 386 coupled with a first side wall 388 by a first diagonal wall390. A bottom wall 392 may be coupled with the first side wall 388 by asecond diagonal wall 394. A second side wall 396 may be coupled with thebottom wall 392 by a third diagonal wall 398. A fourth diagonal wall 400may be provided that couples the second side wall 396 with the top wall386. In some embodiments, the longitudinal beams 358 may have a heightgreater than its width. For example, a height the longitudinal beams 358may be between 1.25 and 2 times greater than its width. This may beachieved, for example, by the first side wall 388 and the second sidewall 396 being between about 1.5 to 2.5 times as long as the top wall386 and the bottom wall 392.

To aid in handling larger forces without adding unnecessary weight, eachof the left longitudinal beam and the right longitudinal beam 358defines an interior comprising a plurality of ribs extending along alength of the right and left longitudinal crash beams 358. The ribs mayextend through the entire interior to couple multiple walls together,thus providing additional material and material thickness to absorb andtransfer greater forces. For example, the right and left longitudinalcrash beams 358 may each include a vertical rib 402 extending from thetop wall 386 to a bottom wall 392 and a horizontal rib 404 extendingfrom the first side wall 388 to the second side wall 396. In otherwords, rib 402 extends from a center of the top wall 386 to a center ofthe bottom wall 392 and rib 404 extends from a center of the first sidewall 388 to a center of the second side wall 396. Spaces 406 defined byan area between the outer walls of each of the left longitudinal beamand the right longitudinal beams 358 and the ribs 402 and 404 arepentagonal in shape. To facilitate the formation of the ribs 402 and404, the left and the right longitudinal beam 358 may be extruded fromaluminum such that the ribs 402 and 404 are formed along with the outerwalls of the longitudinal beams 358. In some embodiments, connectionpoints between the ribs 402 and 404 and the outer walls of thelongitudinal beams 358 may taper outward such that a thickness near theconnection point is greater than a thickness of the rest of the ribs 402and 404. Similarly, junctions of the ribs 402 and 404 with one anothermay also have greater thicknesses than the rest of the ribs 402 and 404.

FIG. 4 shows a bottom view of a rear impact system of vehicle 100. Here,crash beam 358 is coupled with bumper mount 362. Here, bumper mount isshown being secured to the crash beam 358 by having a chamber in which arear end of crash beam 358 is inserted. Bumper mount 362 provides aninterface for coupling the rash beam 358 with rear crash element 364.For example, bumper mount 362 may include a flange or other interfacethat defines apertures for inserting bolts or other fasteners. Fastenersmay be inserted in these apertures and extend into an interior of thecrash element 364 to secure the crash element 364 with the bumper mount362 and crash beam 358. Crash element 364 may provide an interfacebetween the bumper mount 362 and bumper 360, as well as include designcharacteristics that improve the performance of the vehicle 100 in theevent of a rear impact. For example, the crash element 364 may have aflat front surface 370 that is configured to sit flush against a rearsurface of bumper mount 362. The crash element 364 may have a rearsurface 372 that is sloped relative to the front surface to allow thecrash element 364 to be mounted flush against a curved inner surface ofbumper 360. In some embodiments, side walls 374, 376 of the crashelement 364 may be tapered inward from front to back. This allows asmaller connection at the bumper 360, while ensuring a larger contactarea with the bumper mount 362 to help spread out forces from rearimpacts. Crash element 364 may define an open interior having a numberof ribs 446 disposed therein. For example, the interior may includethree ribs 446 that extend from a central portion of the front surface370 to various positions on the rear surface 372 to form a triangulartruss system within the crash element 364. Here, two ribs 446 extend torear corners of the crash element 364 while a third rib 446 extends to acenter portion of the rear surface 372. The truss system helps greatlyincrease the strength and rigidity of the crash element 364 whileminimizing weight and material costs. Here, ribs 446 extend upward in az-direction, unlike most ribs that extend in the x or y-directions. Thisdesign ensures the ribs 446 are connected to and reinforce the frontsurface and back surface of the crash element 364. While shown with opentop and bottom ends, it will be appreciated that the crash element 364may be a closed structure. It will be further appreciated that crashelement 364 may also include chamfered corners and/or dimples to helpthe crash element 364 deform in a desired manner in the event of a rearimpact.

It will be noted that dimples 382 are provided at different distancesfrom the bumper mount 362. This may be done to help compensate for thecurvature of the bumper 360 and the rear of the vehicle 100. By slightlystaggering the dimples 382 along a length of the beam 358, the beam 358may be encouraged to crumple along its longitudinal axis, even in theevent of off-center impacts. It will be appreciated that dimples 382 maybe positioned parallel with one another or in other configurations toachieve the desired collision characteristics for a particular bumperdesign.

FIGS. 5-8 depict an alternative embodiment of a rear impact system ofvehicle 100. The rear impact system is largely similar to that describedelsewhere herein and may include the same or similar features andbenefits. Here, a crash beam 800 having a generally rectangular crosssectional profile may be coupled with a wheel arch 802 and may extendrearward to a flat bumper mount 804 as shown in FIG. 5. Wheel arch 802includes an intricate truss or other reinforcement system that includesa number of reinforcement struts extending between an inner arch and anouter arch of the wheel arch 802. As shown in FIG. 6, several of thesestruts are positioned to support a front edge of the beam 800 to ensurethat the coupling between the wheel arch 802 and beam 800 issufficiently strong. A rear end of the longitudinal crash beam 800 iscoupled with a flat bumper mount 804 as shown in FIG. 7. Beam 800 isshown having a generally rectangular cross-sectional profile, althoughin some embodiments, one or more of the sides may be positioned atirregular angles relative to one another. For example, a top side may beangled upward by having the left and right sides be of differentlengths. In some embodiments, the beam 800 may include chamfered cornersand/or dimples as described in accordance with beam 358. Outer walls ofbeam 800 may define an open interior that contains a number of ribs 806.Ribs 806 may be similar to those described above, and may connectmultiple surfaces of the beam 800 together within the interior of beam800. For example, a horizontal rib 806 and a vertical rib 806 may bisectthe interior of beam 800, thereby creating four generally rectangularchambers that extend along a length of the beam 800. It will beappreciated that other rib designs may be contemplated, with the mainpurpose of the beams being to add strength and rigidity whileeliminating the weight associated with solid beams. Bracket mount 804 isshown here as a generally flat plate that may be mounted to a flat rearend of the beam 800. As shown in FIG. 8, bumper mount 804 provides aflat mounting surface on which a crash element and/or bumper, such ascrash element 364 and bumper 360 described above, may be mounted. Forexample, the bumper mount 804 includes a flange 808 that extends beyondan outer periphery of the beam 800 and provides space through whichfasteners and/or other securement mechanisms may be applied to secure acrash element and/or bumper with the beam 800.

FIG. 9 shows another embodiment of a rear impact system of vehicle 100.Here, longitudinal beam 900 is shown having an irregular shape thatmatches a forward end of a bumper mount 902. Here, beam 900 includes oneor more dimples 904 that are configured to encourage the beam 900 tocrumple in an accordion-like manner as described elsewhere herein.Bumper mount 902 may define one or more apertures that are configured toreceive fasteners for securing a crash element 906 with the bumper mount902. Crash element 906 is largely similar to the crash element 364described above, and may be used to couple the bumper mount 902 with abumper 908. Here, crash element 906 includes dimples 910 that operatesimilar to other dimples described herein. While shown as a closedcomponent, it will be appreciated that crash element 906 may have anopen top or bottom surface and/or may define an open interior having anumber of ribs that extend along one or more of the x, y, or z axis ofthe crash element 906.

FIG. 10 is a flowchart depicting a process 1000 for absorbing a rearimpact with an electric vehicle. Process 1000 may be performed using theelectric vehicle 100 described herein. Process 1000 may begin at block1002 by receiving a collision at a rear end of the electric vehicle. Theimpact may be received by a rear bumper or other rear component of thevehicle that is coupled with a longitudinal beam. At block 1004, forcemay be absorbed using a plurality of ribs of a rear crash element of theelectric vehicle. The rear crash element may be coupled with the rearbumper and may define an interior comprising the plurality of ribs. Eachof the ribs may extend between a front surface and a rear surface of therear crash element, such as in a z-direction. The ribs, and possibledimples formed in the sides of the crash element, may help the crashelement properly deform and transfer and absorb force. At block 1006,force may be transferred from a rear edge of the rear crash element toat least one crash beam that is coupled with a front edge of the rearcrash element. The crash beam may be directly coupled with the crashelement and/or may be coupled via a bumper mount positioned between thetwo components.

A force from the collision may be transferred from a rear edge of the atleast one crash beam to a medial portion of the at least one crash beamat block 1008. The crash beam may be coupled with a rear portion of achassis or rear wheel arch of the electric vehicle and may extend to therear end of the electric vehicle. Process 1000 may also includeabsorbing at least a portion of the force from the collision with theouter walls and a number of ribs of the longitudinal beam. For example,as the force of the impact travels through the longitudinal beam, theforce is absorbed by the additional material and thickness provided bythe ribs. Any remaining forces may then be transferred to the rear endof the rear wheel arch or other component coupled with a front end ofthe longitudinal beam. The crash beam may be coupled with a rear portionof a rear wheel arch of the electric vehicle. At block 1010, anyremaining portion of the force may be transferred to the rear end of therear wheel arch.

Oftentimes, there will be a rear impact system positioned on either sideof a trunk or motor compartment of the vehicle. This provides protectionagainst impacts to both the left and right rear portions of the electricvehicle. In instances where an impact is received across an entire rearof the vehicle, both sides of the vehicle may absorb and transfer forcefrom the impact as described in process 1000.

It should be noted that the systems and devices discussed above areintended merely to be examples. It must be stressed that variousembodiments may omit, substitute, or add various procedures orcomponents as appropriate. Also, features described with respect tocertain embodiments may be combined in various other embodiments.Different aspects and elements of the embodiments may be combined in asimilar manner. Also, it should be emphasized that technology evolvesand, thus, many of the elements are examples and should not beinterpreted to limit the scope of the invention.

Specific details are given in the description to provide a thoroughunderstanding of the embodiments. However, it will be understood by oneof ordinary skill in the art that the embodiments may be practicedwithout these specific details. For example, well-known structures andtechniques have been shown without unnecessary detail in order to avoidobscuring the embodiments. This description provides example embodimentsonly, and is not intended to limit the scope, applicability, orconfiguration of the invention. Rather, the preceding description of theembodiments will provide those skilled in the art with an enablingdescription for implementing embodiments of the invention. Variouschanges may be made in the function and arrangement of elements withoutdeparting from the spirit and scope of the invention.

Having described several embodiments, it will be recognized by those ofskill in the art that various modifications, alternative constructions,and equivalents may be used without departing from the spirit of theinvention. For example, the above elements may merely be a component ofa larger system, wherein other rules may take precedence over orotherwise modify the application of the invention. Also, a number ofsteps may be undertaken before, during, or after the above elements areconsidered. Accordingly, the above description should not be taken aslimiting the scope of the invention.

Also, the words “comprise”, “comprising”, “contains”, “containing”,“include”, “including”, and “includes”, when used in this specificationand in the following claims, are intended to specify the presence ofstated features, integers, components, or steps, but they do notpreclude the presence or addition of one or more other features,integers, components, steps, acts, or groups.

What is claimed is:
 1. A rear impact system for an electric vehicle, the rear impact system comprising: a bumper extending laterally along a rear of the electric vehicle; a left rear crash element coupled proximate a left end of the bumper, wherein the left rear crash element defines a first interior comprising a first plurality of ribs extending between a first front surface and a first rear surface of the left rear crash element; a right rear crash element coupled proximate a right end of the bumper, wherein the right rear crash element defines a second interior comprising a second plurality of ribs extending between a second front surface and a second rear surface of the right rear crash element; a left bumper mount that couples the left rear crash element with the bumper; a right bumper mount that couples the right rear crash element with the bumper; a left crash beam having a first front end that is received within a left rear portion of a left rear wheel arch of the electric vehicle and a first rear end that is coupled with the left rear crash element of the electric vehicle, wherein the left rear crash element extends between a rear end of the left crash beam and the bumper, wherein the left crash beam has an octagonal cross-section; and a right crash beam having a second front end that is received within a right rear portion of a right rear wheel arch of the electric vehicle and a second rear end that is coupled with the right rear crash element of the electric vehicle, wherein the right rear crash element extends between a rear end of the right crash beam and the bumper, wherein the right crash beam has an irregular octagonal cross-section.
 2. The rear impact system for an electric vehicle of claim 1, wherein: the plurality of ribs comprises: a first rib that extends from a medial portion of the front surface to a first end of the rear surface; a second rib that extends from the medial portion of the front surface to a second end of the rear surface; and a third rib that extends from the medial portion of the front surface to a medial portion of the rear surface.
 3. The rear impact system for an electric vehicle of claim 2, wherein: each of the first rib, the second rib, and the third rib extends from a same position on the front surface of the rear crash element.
 4. The rear impact system for an electric vehicle of claim 1, wherein: the plurality of ribs divides the interior of the rear crash element into triangular sections.
 5. The rear impact system for an electric vehicle of claim 1, wherein: the rear crash element comprises a left surface and a right surface that couple the front surface with the rear surface.
 6. The rear impact system for an electric vehicle of claim 5, wherein: the left surface extends from the front surface at a different angle than the right surface.
 7. The rear impact system for an electric vehicle of claim 1, wherein: the first plurality of ribs and the second plurality of ribs extend vertically along a height of the respective rear crash element.
 8. The rear impact system for an electric vehicle of claim 1, wherein: each of the left crash beam and the right crash beam define one or more dimples that extend into at least two sidewalls of the respective crash beam.
 9. A rear impact system for an electric vehicle, the rear impact system comprising: a bumper extending laterally along a rear of the electric vehicle; a left rear crash element coupled proximate a left end of the bumper; a right rear crash element coupled proximate a right end of the bumper, wherein each of the left rear crash element and the right crash element comprises a left surface, a right surface, a front surface, and a rear surface that define an interior comprising a plurality of ribs extending between a front surface and a rear surface of the respective rear crash element, wherein the right surface and the left surface have different lengths; a left bumper mount that couples the left rear crash element with the bumper; a right bumper mount that couples the right rear crash element with the bumper; a left crash beam; and a right crash beam, wherein: each of the left crash beam and the right crash beam comprises a front end of each is received within a rear portion of a respective rear wheel arch of the electric vehicle and a rear end that is coupled with a respective one of the left rear crash element or the right crash element; and each of the left crash beam and the right crash beam has an irregular octagonal cross-section.
 10. The rear impact system for an electric vehicle of claim 9, wherein: the plurality of ribs comprises: a first rib that extends from a medial portion of the front surface to a first end of the rear surface; a second rib that extends from the medial portion of the front surface to a second end of the rear surface; and a third rib that extends from the medial portion of the front surface to a medial portion of the rear surface.
 11. The rear impact system for an electric vehicle of claim 9, wherein: the plurality of ribs divides the interior of the respective rear crash element into triangular sections.
 12. The rear impact system for an electric vehicle of claim 9, wherein: each of the left crash beam and the right crash beam defines a beam interior comprising an additional plurality of ribs extending in a longitudinal direction.
 13. The rear impact system for an electric vehicle of claim 12, wherein: each additional plurality of ribs comprises: a vertical rib extending from a top wall of one of the crash beams to a bottom wall of the one of the crash beams; and a horizontal rib extending from a first side wall of the one of the crash beams to a second side wall of the one of the crash beams.
 14. The rear impact system for an electric vehicle of claim 9, wherein: spaces defined by an area between outer walls of each of the left crash beam and the right crash beam and the plurality of ribs are pentagonal in shape.
 15. A method of absorbing a rear impact with an electric vehicle, the method comprising: receiving a collision at a bumper of the electric vehicle; absorbing force using a plurality of ribs of each of a left rear crash element and a right rear crash element of the electric vehicle via bumper mounts coupled with each of the rear crash elements, wherein each of the left rear crash element and the right rear crash element defines an interior comprising the plurality of ribs, wherein each of the plurality of ribs extends between a front surface and a rear surface of the respective rear crash element; transferring force from a rear edge of each respective rear crash element to at least one crash beam that is coupled with a front edge of each respective rear crash element, wherein the at least one crash beam comprises an irregular octagonal cross-section; transferring a force from the collision from a rear edge of the at least one crash beam to a medial portion of the at least one crash beam, the at least one crash beam being received within a rear portion of a rear wheel arch of the electric vehicle and extending to the rear end of the electric vehicle; and transferring any remaining portion of the force to the rear end of the rear wheel arch.
 16. The method of absorbing a rear impact with an electric vehicle of claim 15, wherein: the at least one crash beam defines an interior comprising an additional plurality of ribs extending in a crash direction from the rear edge through the medial portion to a front edge of the at least one crash beam; and the method further comprises absorbing at least a portion of the force from the collision with the outer walls and the additional plurality of ribs of the at least one crash beam.
 17. The method of absorbing a rear impact with an electric vehicle of claim 15, wherein: the at least one crash beam is configured to crumple longitudinally when subjected to a rear impact to absorb a portion of force from the rear impact.
 18. The method of absorbing a rear impact with an electric vehicle of claim 15, wherein: the plurality of ribs comprises: a first rib that extends from a medial portion of the front surface to a first end of the rear surface; a second rib that extends from the medial portion of the front surface to a second end of the rear surface; and a third rib that extends from the medial portion of the front surface to a medial portion of the rear surface.
 19. The method of absorbing a rear impact with an electric vehicle of claim 15, wherein: the plurality of ribs divides the interior of the rear crash element into triangular sections.
 20. The method of absorbing a rear impact with an electric vehicle of claim 15, wherein: the at least one crash beam comprises: a top wall coupled with a first side wall by a first diagonal wall; a bottom wall coupled with the first side wall by a second diagonal wall; a second side wall coupled with the bottom wall by a third diagonal wall; and a fourth diagonal wall that couples the second side wall with the top wall. 